U0097 indicates that the vehicle's communication bus H has an open circuit, meaning the data line cannot carry signals between the modules that share this bus. The loss of continuity prevents normal module-to-module communication and typically sets the malfunction indicator lamp.
A broken wire, corroded terminal, or loose connector on the bus H circuit creates an open that stops signal flow.
A module such as the ABS, TCM, or body control module may have an internal bus driver failure that presents as an open on the shared line.
If the required 120‑ohm termination resistor at the end of bus H is absent or open, the bus will appear open to the network.
The module that manages bus H arbitration can develop an internal fault that leaves the bus in an open state.
Rarely, the powertrain control module's own bus H driver can fail, but this is only considered after all external wiring and modules are verified good.
Not usually. The code most often points to an open wiring fault, a bad connector, a missing termination resistor, or a faulty module on bus H. PCM failure is rare and should be confirmed only after all other causes are eliminated.
Yes. The CAN bus requires a 120‑ohm termination at each end; if one is open or missing, the bus will appear open and set U0097.
Use a scan tool that can display live bus voltage or a multimeter to measure the differential voltage on the bus H wires while the vehicle is powered. An open circuit will show no differential voltage or an infinite resistance reading.
No. Replacing the PCM without confirming an internal bus driver fault wastes time and money. Follow the diagnostic sequence to rule out wiring, connectors, termination resistors, and other modules first.